History of diabetes, clinical features of prostate cancer, and prostate cancer recurrence-data from CaPSURE (United States)

Role of single nucleotide polymorphisms of the HSD3B1 gene (rs6203 and rs33937873) in the prediction of prostate cancer risk

3-β-hydroxysteroid dehydrogenase 1 (HSD3B1) is shown to affect dihydrotestosterone level in prostatic tissue which is a risk factor for prostate cancer (PC). The present study aimed to determine whether rs33937873 (G313A) and rs6203 (C338T) single nucleotide polymorphisms (SNP) in HSD3B1 gene was a potential risk factor for PC susceptibility and can predict the recurrence of PC in Egyptian patients. A total of 186 Egyptian patients were selected with incident primary PC and compared with 180 age healthy controls. The frequencies and the main effect of rs33937873 and rs6203 in HSD3B1 were compared and investigated between the patients and control using genotyping technique and statistical analysis. The mutant GA genotype of G313A in rs33937873 SNP was considered as an independent risk for PC in the multivariate regression analysis [odds ratio (OR)=2.7, 95% confidence intervals (CI): 1.2-5.5, P=0.01] together with positive history of hypertension (HTN) (OR=6.2, 95% CI: 3.2-12.1, P=0.0001) and begin prostatic hyperplasia (BPH; OR=8.9, 95% CI: 4.5-17.5, P=0.0001). Conversely, in rs6203 (C338T), C allele is considered as major risk allele in the development of PC (OR=1.8, 95% CI: 1.3-2.4, P=0.0003). The univariate logistic regression analyses indicated that CC genotype of rs6203 was a PC risk factor (OR=1.9, 95% CI: 1.3-2.9, P=0.002). In addition, the frequency of the A-C haplotype established by rs33937873-rs6203 was also significantly higher for PC (P=0.013). The predication of PC recurrence was associated only with positive family history (OR=7.7, 95% CI: 2.3-25.9, P=0.001) and not for The G313A and C338T SNPs. These results suggested that the two HSD3B1 polymorphisms rs33937873 and rs6203 may modify the risk of PC, particularly among patients with HTN and history of BPH, suggesting them as prominent future markers for prediction of PC risk.

Are Diabetic Patients at Increased Risk for Biochemical Recurrence After Radical Prostatectomy?

Introduction

Diabetic patients are at a lower risk for prostate cancer. However, the relationship between diabetes mellitus (DM) and biochemical recurrence (BCR) after radical prostatectomy (RP) is less clear. The goal of our study was to determine diabetes's value as a biochemical recurrence predictor.

Materials and methods

We conducted a retrospective analysis of 117 patients who had undergone open radical prostatectomy between 1999 and 2021 at our institution. Univariate and multivariate statistical analyses were used to identify factors associated with biochemical recurrence.

Results

On univariate analysis, factors associated with biochemical recurrence were diabetes (p=0.002), preoperative prostate-specific antigen (PSA) levels (p=0.022), positive digital rectal exam (p=0.035), number of positive biopsy cores (p<0.001), unfavorable intermediate risk group (p=0.014), peri-neural invasion (PNI) on RP specimen (p=0.043), tumor volume (p=0.011), and positive surgical margins (p<0.001). Multivariate analysis showed that factors independently associated with biochemical recurrence were diabetes (p=0.039; OR=2.788), number of positive cores (p=0.016; OR=4.124), and positive surgical margins (p=0.008; OR=3.876).

Conclusion

A history of diabetes mellitus should be taken into consideration when assessing patients’ risk of biochemical recurrence after radical prostatectomy. More research on a larger scale is needed to determine diabetes' value as a biochemical predictor.

Hormonal patterns in men with prediabetes and diabetes in NHANES III: possible links with prostate cancer

PURPOSE

Pathways involving sex hormones and insulin-like growth factors (IGFs) have been proposed to explain, in part, the lower risk of prostate cancer among men with diabetes. To gain insights into potential biological mechanisms we explored differences in serum concentrations of sex hormones and IGFs across the trajectory from normoglycemia to prediabetes to poorly controlled diabetes.

METHODS

Using cross-sectional data from the National Health and Nutrition Examination Survey III we examined differences in levels of circulating sex hormones, sex hormone-binding globulin (SHBG), IGF-1, and IFG-binding protein 3 (IGFBP-3), according to diabetes status: no diabetes [n = 648], prediabetes [n = 578], undiagnosed diabetes [n = 106], well-controlled diabetes [n = 42], and poorly controlled diabetes [n = 56]. Adjusted geometric mean concentrations were derived using multivariable linear regression, adjusted for age, race, and other lifestyle factors.

RESULTS

Total testosterone concentrations were lower among prediabetics (4.89 ng/mL, 95% confidence interval (CI) 4.95-5.21) than men without prediabetes/diabetes (5.29 ng/mL, 95% CI 5.06-5.53) but did not reduce further across diabetes groups. Concentrations of estradiol, estimated free testosterone, SHGB, IGF-1, and IGFBP-3 did not differ. While the ratio of IGF-1 to IGFBP-3 was lower among men with prediabetics and undiagnosed diabetes than men without prediabetes/diabetes, there was no trend across groups. A positive trend for the ratio of estradiol-to-testosterone levels was observed across groups (p trend = 0.045).

CONCLUSION

Our findings do not provide clear support for either an androgen driven or IGF-driven pathway for the inverse association between diabetes and prostate cancer risk.

Population-wide impacts of aspirin, statins, and metformin use on prostate cancer incidence and mortality

We evaluated the association between aspirin, statins, and metformin use and prostate cancer (PC) incidence and mortality using a large population-based dataset. 388,760 men who participated in national health screening program in Korea during 2002–2003 were observed from 2004 to 2013. Hazard ratios of aspirin, statins, and metformin use for PC incidence and PC mortality were calculated with adjustment for simultaneous drug use. Cumulative use of each drug was inserted as time-dependent variable with 2-year time windows. Aspirin use ≥ 1.5 year (per 2-year) was associated with borderline decrease in PC mortality when compared to non-users (adjusted hazard ratio [aHR] 0.71, 95% confidence interval [CI] 0.50–1.02). Statins use was not associated with either PC incidence or PC mortality. Metformin ever-use was associated with decreased PC incidence compared with non-diabetics (aHR 0.86, 95% CI 0.77–0.96). Diabetics who were not using metformin or using low cumulative doses had higher PC mortality than non-diabetics (aHR 2.01, 95% CI 1.44–2.81, and aHR 1.70, 95% CI 1.07–2.69, respectively). However, subjects with higher cumulative doses of metformin did not show increased PC mortality. In conclusion, metformin use was associated with lower PC incidence. Use of aspirin and that of metformin among diabetic patients were associated with lower PC mortality.

Trends in cancer mortality among people with vs without diabetes in the USA, 1988-2015

AIMS/HYPOTHESIS

Cancer-related death is higher among people with vs without diabetes. However, it is not known if this excess risk has changed over time or what types of cancer may be driving these changes.

METHODS

To estimate rates of site-specific cancer mortality in adults with vs without self-reported diagnosed diabetes, we used data from adults aged ≥18 years at the time of the interview who participated in the 1985-2012 National Health Interview Survey. Participants' data were linked to the National Death Index by the National Center for Health Statistics to determine vital status and cause of death through to the end of 2015. Cancer deaths were classified according to underlying cause of death. Death rates for five time periods (1988-1994, 1995-1999, 2000-2004, 2005-2009, 2010-2015) were estimated using discrete Poisson regression models adjusted for age, sex and race/ethnicity with p for linear trend reported (p_trend). Site-specific cancer mortality rates were stratified by diabetes status and period, and total cancer mortality rates were additionally stratified by sex, race/ethnicity, education and BMI status.

RESULTS

Among adults with diabetes, age-adjusted cancer mortality rates (per 10,000 person-years) declined 25.5% from 39.1 (95% CI 30.1, 50.8) in 1988-1994 to 29.7 (26.6, 33.1) in 2010-2015, p_trend < 0.001. Among adults without diabetes, rates declined 25.2% from 30.9 (28.6, 33.4) in 1988-1994 to 23.2 (22.1, 24.2) in 2010-2015, p_trend < 0.01. Adults with diabetes remained approximately 30% more likely to die from cancer than people without diabetes, and this excess risk did not improve over time. In adults with diabetes, cancer mortality rates did not decline in some population subgroups (including black people, people with lower levels of education and obese people), and the excess risk increased for obese adults with vs without diabetes. Declines in total cancer mortality rates in adults with diabetes appear to be driven by large relative declines in cancers of the pancreas (55%) and breast (65%), while for lung cancer, declines are modest (7%).

CONCLUSIONS/INTERPRETATION

Declines in cancer mortality rates were observed in adults with and without diabetes. However, adults with diabetes continue to be more likely to die from cancer than people without diabetes. This study highlights the continued need for greater cancer risk-factor mitigation, especially in adults with diabetes.

Blood glucose, glucose balance, and disease-specific survival after prostate cancer diagnosis in the Finnish Randomized Study of Screening for Prostate Cancer

INTRODUCTION

Diabetes mellitus has been linked with adverse prostate cancer (PCa) outcomes. However, role of hyperglycemia in PCa progression is unclear. We evaluated the link between hyperglycemia and PCa survival among Finnish PCa patients.

METHODS

The study cohort included 1770 men with data on fasting glucose and diagnosed with PCa within the Finnish Randomized Study of Screening for PCa in 1995-2009. Additionally, 1398 men had data on glycated hemoglobin (HbA1c). Information on fasting glucose and HbA1c measurements was obtained from the regional laboratory database. Antidiabetic medication use was obtained from the prescription database of the Social Insurance Institution (SII). Time-dependent Cox regression analysis was used to estimate hazard ratios (HRs) and 95% confidence intervals for PCa death among diabetic, impaired glucose tolerant, and normoglycemic men.

RESULTS

During median follow-up of 9.9 years after the diagnosis, 182 men died from PCa. After adjustment for tumor stage, Gleason grade, and PSA level at diagnosis, diabetic fasting glucose level after PCa diagnosis was associated with elevated risk of PCa death compared to normoglycemic men (HR 1.67 95% CI 1.18-2.36). The risk association was strongest among participants with localized cancer at diagnosis; HR 2.39, 95% CI 1.45-3.93. The risk elevation was observed for glucose measurements taken up to 5 years earlier. Diabetic glucose levels measured before the diagnosis were not associated with PCa death.

CONCLUSION

Our study cohort suggests an increased risk of PCa death in men with diabetic fasting blood glucose levels, supporting the role of hyperglycemia as a risk factor for PCa progression.

Interaction between Comorbidity and Cancer

Background

Older patients have an average of three comorbidities in addition to their cancer. Oncologic studies have usually ignored this aspect when adjusting for confounders. There is mounting evidence that comorbidity interacts with risk, survival, disease progression, and treatment of elderly patients with cancer. The strength of many of these interactions increases with age.

Methods

A review of the literature was undertaken regarding two of these interactions: cancer risk and prognosis.

Results

In older patients, the risk and behavior of cancer can be strongly affected by comorbidities and their related treatment. Rather than a blanket effect, this effect might be attached to groups of syndromes with common pathophysiologic mechanisms. This is notably true for metabolic disorders and inflammatory diseases.

Conclusions

In addition to focusing on the influence of cancer treatment on comorbidity or on the effect of comorbidity in delivering cancer treatment, future endeavors will need to consider the direct impact of comorbidity on the risk and the behavior of the cancer in elderly patients.

The Association of Diabetes and Obesity With Prostate Cancer Progression: HCaP-NC

BACKGROUND

The role of race in modifying the association among diabetes, obesity, and prostate cancer (CaP) progression is not well studied. We evaluated diabetes and obesity in association with time to CaP progression in White Americans (Whites) and Black Americans (Blacks).

METHODS

Our study sample consisted of 363 White and 284 Black research participants from the Health Care Access and CaP Treatment in North Carolina (HCaP-NC) cohort. The association between self-reported diabetes or obesity and CaP progression (mean follow-up time approximately 5 years) was assessed using Cox proportional hazards modeling, with adjustment for potential confounders. Stratum-specific hazard ratio (HR) estimates for Whites and Blacks were evaluated.

RESULTS

Self-reported diabetes was not associated with CaP progression in the cohort as a whole (HR: 0.86, 95%CI: 0.54, 1.35), or among racially defined groups (Whites, HR: 1.03, 95%CI: 0.50, 2.13 or Blacks, HR: 0.77, 95%CI: 0.43, 1.39). Obesity was positively associated with CaP progression among Whites, in models including (HR: 1.79, 95%CI: 1.08, 2.97), and excluding (HR: 1.80, 95%CI: 1.09, 2.96) diabetes as a covariate. No association was observed between obesity and CaP progression in Blacks or the cohort as whole.

CONCLUSIONS

Self-reported diabetes was not associated with CaP progression In HCaP-NC. Obesity was associated with CaP progression only among White research participants. Prostate 77:878-887, 2017. © 2017 Wiley Periodicals, Inc.

The association of diabetes and obesity with prostate cancer aggressiveness among Black Americans and White Americans in a population-based study

PURPOSE

Few studies have investigated the role of race in the association of diabetes and obesity with prostate cancer aggressiveness. Here we evaluate the independent association between diabetes and obesity with prostate cancer aggressiveness in White Americans and Black Americans.

METHODS

Our cross-sectional, case-only study consisted of 1,058 White Americans and 991 Black Americans from the North Carolina-Louisiana Prostate Cancer (PCaP) project. Diabetes status was determined by self-report. Obesity was determined using body mass index and calculated based on anthropometric measurements. High aggressive prostate cancer was defined as Gleason sum ≥8, or prostate-specific antigen >20 ng/ml, or Gleason sum = 7 and clinical stage cT3-cT4. The association between diabetes and obesity with high aggressive prostate cancer at diagnosis was evaluated using multivariable logistic regression and adjusted for potential confounders.

RESULTS

Diabetes was not associated with high aggressive prostate cancer in the overall sample (OR 1.04; 95% CI 0.79, 1.37), White Americans (OR 1.00; 95% CI 0.65, 1.57) or Black Americans (OR 1.07; 95% CI 0.75, 1.53). Obesity, independent of diabetes, was positively associated with high aggressive prostate cancer in White Americans (OR 1.98; 95% CI 1.14, 3.43), but not in the overall sample (OR 1.37; 95% CI 0.99, 1.92) or Black Americans (OR 1.09; 95% CI 0.71, 1.67).

CONCLUSIONS

Diabetes was not associated with prostate cancer aggressiveness, overall, or in either race group. Obesity, independent of diabetes, was associated with high aggressive prostate cancer only in White Americans.

Diabetes and mortality in patients with prostate cancer: a meta-analysis

BACKGROUND

There are conflicting results as to the association between pre-existing diabetes and the risk of mortality in patients with prostate cancer. The purpose of this study is to estimate the influence of pre-existing diabetes on prostate cancer-specific mortality and all-cause mortality.

METHODS

We searched PubMed and Embase to identify studies that investigated the association between pre-existing diabetes and risk of death among men with prostate cancer. Pooled risk estimates and 95 % confidence intervals were calculated using fixed-effects models or random-effects models. Heterogeneity tests were conducted between studies. Publication bias was analyzed by using the Egger's test, Begg's test, and the trim and fill method.

RESULTS

Of the 733 articles identified, 17 cohort studies that had 274,677 male patients were included in this meta-analysis. Pre-existing diabetes was associated with a 29 % increase in prostate cancer-specific mortality [relative risk (RR) 1.29, 95 % CI 1.22-1.38, I(2) = 66.68 %], and with a 37 % increase in all-cause mortality (RR 1.37, 95 % CI 1.29-1.45, p < 0.01, I(2) = 90.26 %). Additionally, in a subgroup analysis that was a type specific analysis focusing on type 2 diabetes and was conducted only with three cohort studies, pre-existing type 2 diabetes was associated with all-cause mortality (RR 2.01, 95 % CI 1.37-2.96, I(2) = 95.55 %) and no significant association with prostate cancer-specific mortality was detected (RR 1.17, 95 % CI 0.96-1.42, I(2) = 75.59 %). There was significant heterogeneity between studies and no publication bias was found.

CONCLUSIONS

This meta-analysis suggests diabetes may result in a worse prognosis for men with prostate cancer. Considering heterogeneity between studies, additional studies should be conducted to confirm these findings, and to allow generalization regarding the influence that each type of diabetes has on prostate cancer mortality.

Preoperative glycemic control status as a significant predictor of biochemical recurrence in prostate cancer patients after radical prostatectomy

Background

The effect of diabetes mellitus (DM) on prostate cancer (PCa) outcome remains controversial. Thus, we investigated the association of DM history, glycemic control, and metformin use with oncologic outcomes after radical prostatectomy (RP).

Methods

We reviewed the records of 746 contemporary patients who had hemoglobin A1c (HbA1c) measured within the 6 months preceding RP. The associations between clinical variables and risk of adverse pathological features and biochemical recurrence (BCR) were tested using a multivariate logistic regression and multiple Cox-proportional hazards model, respectively. BCR was defined as prostatic specific antigen (PSA) > 0.2 ng/mL in 2 consecutive tests.

Results

There were no significant differences in the rates of adverse pathologic features and BCR-free survival between patients with (n = 209) and without (n = 537) a history of DM diagnosis (all p > 0.05). In multivariate analyses, high HbA1c level (≥ 6.5%) was significantly related with high pathologic Gleason score (≥ 4+3; odds ratio [OR] 1.704, p = 0.019) and BCR-free survival (OR 1.853, p = 0.007). Metformin use was not associated with BCR-free survival (OR 0.662, p = 0.125).

Conclusions

Poor glycemic control was significantly associated with BCR after RP. Meanwhile, metformin use was not associated with biochemical outcome after RP. Further investigation would be needed to identify exact mechanism underlying the impact of glycemic control on PCa treatment outcome.

Metabolic syndrome in the development and progression of prostate cancer

Prostate cancer (PCa) is the most common noncutaneous malignancy and second leading cause of cancer-specific mortality for men in the United States. There is a wide spectrum of aggressiveness ranging from biologically significant to indolent disease, which has led to an interest in the identification of risk factors for its development and progression. Emerging evidence has suggested an association between metabolic syndrome (MetS) and PCa. MetS represents a cluster of metabolic derangements that confer an increased risk of cardiovascular disease and type 2 diabetes mellitus. Its individual components include obesity, dyslipidemias, high blood pressure, and high fasting glucose levels. MetS has become pervasive and is currently associated with a high socioeconomic cost in both industrialized and developing countries throughout the world. The relationship between MetS and PCa is complex and yet to be fully defined. A better understanding of this relationship will facilitate the development of novel therapeutic targets for the prevention of PCa and improvement of outcomes among diagnosed men in the future. In this review, we evaluate the current evidence on the role of MetS in the development and progression of PCa. We also discuss the clinical implications on the management of PCa and consider the future direction of this subject.

Poor glycemic control of diabetes mellitus is associated with higher risk of prostate cancer detection in a biopsy population

OBJECTIVES

To evaluate the impact of glycemic control of diabetes mellitus (DM) on prostate cancer detection in a biopsy population.

PATIENTS AND METHODS

We retrospectively reviewed the records of 1,368 men who underwent prostate biopsy at our institution. We divided our biopsy population into three groups according to their history of DM, and their Hemoglobin A1c (HbA1c) level: a no-DM (DM-) group; a good glycemic control (DM+GC) group (HbA1c <6.5%); and a poor glycemic control (DM+PC) group (HbA1c ≥6.5%). For sub-analyses, the DM+PC group was divided into a moderately poor glycemic control (DM+mPC) group (6.5≤ HbA1c <7.5%) and a severely poor glycemic control (DM+sPC) group (HbA1c ≥7.5%).

RESULTS

Among 1,368 men, 338 (24.7%) had a history of DM, and 393 (28.7%) had a positive biopsy. There was a significant difference in prostatic specific antigen density (PSAD) (P = 0.037) and the frequency of abnormal DRE findings (P = 0.031) among three groups. The occurrence rate of overall prostate cancer (P<0.001) and high-grade prostate cancer (P = 0.016) also presented with a significantly difference. In the multivariate analysis, the DM+PC group was significantly associated with a higher rate of overall prostate cancer detection in biopsy subjects compared to the DM- group (OR = 2.313, P = 0.001) but the DM+PC group was not associated with a higher rate of high-grade (Gleason score ≥7) diseases detected during the biopsy (OR = 1.297, P = 0.376). However, in subgroup analysis, DM+sPC group was significantly related to a higher risk of high-grade diseases compared to the DM- group (OR = 2.446, P = 0.048).

CONCLUSIONS

Poor glycemic control of DM was associated with a higher risk of prostate cancer detection, including high-grade disease, in the biopsy population.

Type 2 diabetes: a protective factor for prostate cancer? An overview of proposed mechanisms

Diabetes mellitus and prostate cancer are 2 of the most important public health concerns, especially in the elderly population. Although diabetes has been recognized as a potent risk factor for many types of cancers, there is a large amount of evidence that shows that it has a protective role against prostate cancer. The underlying cause of this protective role is not fully understood, however, some mechanisms have been proposed in this area. In the present study we have reviewed these mechanisms and some new mechanisms are also proposed.

Hyperglycemia and prostate cancer recurrence in men treated for localized prostate cancer

BACKGROUND

Obesity is consistently linked with prostate cancer (PCa) recurrence and mortality, though the mechanism is unknown. Impaired glucose regulation, which is common among obese individuals, has been hypothesized as a potential mechanism for PCa tumor growth. In this study, we explore the relationship between serum glucose at time of treatment and risk of PCa recurrence following initial therapy.

METHODS

The study group comprised 1734 men treated with radical prostatectomy (RP) or radiation therapy (RT) for localized PCa between 2001-2010. Serum glucose levels closest to date of diagnosis were determined. PCa recurrence was determined based on PSA progression (nadir PSA+2 for RT; PSA≥0.2 for RP) or secondary therapy. Multivariate Cox regression was performed to determine whether glucose level was associated with biochemical recurrence after adjusting for age, race, body mass index, comorbidity, diagnosis of diabetes, Gleason Sum, PSA, treatment and treatment year.

RESULTS

Recurrence was identified in 16% of men over a mean follow-up period of 41 months (range 1-121 months). Those with elevated glucose (≥100 mg/dl) had a 50% increased risk of recurrence (HR 1.5, 95% CI: 1.1-2.0) compared with those with a normal glucose level (<100 mg/dl). This effect was seen in both those undergoing RP (HR 1.9, 95% CI: 1.0-3.6) and those treated with RT (HR 1.4, 95% CI: 1.0-2.0).

CONCLUSIONS

Glucose levels at the time of PCa diagnosis are an independent predictor of PCa recurrence for men undergoing treatment for localized disease.

Diabetes mellitus and prostate cancer risk of different grade or stage: a systematic review and meta-analysis

AIM

Prior studies have reported that diabetes mellitus might reduce the overall prostate cancer risk. We examined this association by conducting a detailed meta-analysis of the studies published in peer-reviewed literature on the association between diabetes mellitus and prostate cancer risk of different stage or grade.

METHODS

A comprehensive search for articles of MEDLINE and EMBASE databases and bibliographies of retrieved articles published up to October 23, 2012 was performed. Methodological quality assessment of the trials was based on the Newcastle-Ottawa Scale. Meta-analysis was performed using STATA 12.0.

RESULTS

We included 9 studies in the meta-analysis (5 studies examining the relation of different stage only, 2 studies for grade only, and 2 studies for both grade and stage), and found an inverse association between diabetes mellitus and prostate cancer of different stage or grade. The relative risk (RRs) was moderately stronger for low grade (RR 0.74, 95% confidence interval (CI), 0.64-0.86) and localized disease (RR 0.72, 95% CI 0.67-0.76) compared with high grade (RR 0.78, 95% CI 0.67-0.90) and advanced disease (RR 0.85, 95% CI 0.75-0.97).

CONCLUSION

This study suggests an inverse relationship between diabetes mellitus and prostate cancer of different stage or grade. Possible biases underlying this association are discussed.

Diabetes and risk of cancer

Diabetes and cancer represent two complex, diverse, chronic, and potentially fatal diseases. Cancer is the second leading cause of death, while diabetes is the seventh leading cause of death with the latter still likely underreported. There is a growing body of evidence published in recent years that suggest substantial increase in cancer incidence in diabetic patients. The worldwide prevalence of diabetes was estimated to rise from 171 million in 2000 to 366 million in 2030. About 26.9% of all people over 65 have diabetes and 60% have cancer. Overall, 8–18% of cancer patients have diabetes. In the context of epidemiology, the burden of both diseases, small association between diabetes and cancer will be clinically relevant and should translate into significant consequences for future health care solutions. This paper summarizes most of the epidemiological association studies between diabetes and cancer including studies relating to the general all-site increase of malignancies in diabetes and elevated organ-specific cancer rate in diabetes as comorbidity. Additionally, we have discussed the possible pathophysiological mechanisms that likely may be involved in promoting carcinogenesis in diabetes and the potential of different antidiabetic therapies to influence cancer incidence.

The impact of diabetes mellitus on survival in men with clinically localized prostate cancer treated with permanent interstitial brachytherapy

PURPOSE

Patients with cancer of any origin with preexisting diabetes mellitus (DM) are at increased risk for all-cause mortality compared with those without DM. However, the influence of DM on biochemical progression-free survival (bPFS), cause-specific survival (CSS), and overall survival (OS) has not been clearly defined for men with clinically localized prostate cancer treated with brachytherapy.

MATERIALS AND METHODS

From April 1995 to May 2006, 1624 consecutive patients underwent brachytherapy with or without supplemental therapies. A prebrachytherapy diagnosis of diabetes was present in 199 patients (12.3%). Median follow-up was 7.8 years. Cause of death was determined for each deceased patient. Patients with metastatic prostate cancer or castrate-resistant disease without obvious metastases who died of any cause were classified as dead of prostate cancer. All other deaths were attributed to the immediate cause of death.

RESULTS

In patients without (n=1425) and with (n=199) DM, CSS was 97.2% versus 100% (P=0.168), bPFS was 95.6% versus 95.7% (P=0.960), and OS was 77.3% versus 56.0% at 12 years (P=0.003). In Cox regression analysis, OS in nondiabetic patients was most closely related to patient age, coronary artery disease, tobacco consumption, and androgen deprivation. In patients with diabetes, OS was related to patient age and coronary artery disease. In patients without diabetes, CSS was associated with Gleason score and clinical stage. No patient with diabetes died of prostate cancer. Patients with DM were more likely to die of cardiovascular disease (17.8% vs. 12.4%, P=0.007).

CONCLUSIONS

DM does not impact CSS or bPFS after brachytherapy. OS is significantly lower in patients with diabetes due to more deaths from cardiovascular disease.

Diabetes predicts metastasis after radical prostatectomy in obese men: results from the SEARCH database

OBJECTIVE

To examine the association between diabetes and metastasis risk after radical prostatectomy (RP) and to determine if race or obesity modifies this relationship.

PATIENTS AND METHODS

Patients comprised 2058 US veterans with prostate cancer (PCa) enrolled in the Shared Equal-Access Regional Cancer Hospital (SEARCH) database and treated with RP between 1988 and 2010. The association of diabetes with metastasis risk or secondary treatment rates was examined using Cox proportional hazards, adjusting for preoperative and, separately, clinical and postoperative findings. The effect modification by race (black vs white) and obesity (body mass index [BMI] ≥30 vs <30 kg/m(2) ) was tested via interaction terms.

RESULTS

Men with diabetes had higher BMIs and were more likely to be non-white (all P ≤ 0.001). On multivariable analysis, diabetes was not associated with metastasis risk (P ≥ 0.45), but, among men with diabetes, longer diabetes duration was associated with higher metastasis risk (P ≤ 0.035). When stratified by obesity, diabetes was linked with higher metastasis risk in obese but not in non-obese men (P-interaction ≤ 0.037), but there was no significant interaction with race (P-interaction ≥ 0.56). Diabetes also predicted more aggressive secondary treatment among obese men but less aggressive treatment among non-obese men (hazard ratio 1.39 vs 0.63, P-interaction = 0.006). Where applicable, results were similar for both pre- and postoperative models.

CONCLUSIONS

Diabetes was not associated with metastasis risk overall. Stratification by obesity yielded significant differences, with diabetes linked to a fourfold higher metastasis risk in obese men, despite predicting more aggressive secondary treatment. Longer diabetes duration was also associated with increased metastasis risk.

Diabetes mellitus is associated with short prostate-specific antigen doubling time after radical prostatectomy

OBJECTIVE

To investigate whether diabetes mellitus (DM) was associated with postoperative outcomes, including prostate-specific antigen doubling time, among men who underwent radical prostatectomy (RP) for clinically localized prostate cancer (PCa).

METHODS

Data of 661 patients who underwent radical prostatectomy for node-negative prostate cancer and were followed up for ≥3 years postoperatively at our institution were analyzed. Associations between diabetes mellitus at surgery and outcomes following radical prostatectomy, such as biochemical recurrence-free survival and prostate-specific antigen doubling time, were examined. Aggressive recurrence was defined as biochemical recurrence with prostate-specific antigen doubling time <9 months.

RESULTS

Of the 661 total subjects, DM (n = 67, 10.1 %) and non-DM group (n = 594, 89.9 %) showed no significant differences in various clinicopathologic parameters including age and PSA. DM group had lower postoperative biochemical recurrence-free survival than non-DM group, with observed difference approaching statistical significance (log-rank, p = 0.077). On multivariate analysis, DM at surgery was significantly associated with aggressive recurrence following RP (p = 0.048). Pathologic Gleason score (p = 0.008) and seminal vesicle invasion (p = 0.010) were also significantly associated with aggressive recurrence on multivariate analysis.

CONCLUSION

Our results show that pre-existing DM in men with PCa is associated with more aggressive recurrence, suggesting that DM may affect disease progression following RP. Further investigation would be needed to elucidate exact biologic interaction between DM and PCa and also assess causal relationships that potentially could be modified to improve long-term outcome in patients with the two diseases.

Diabetes and cancer (2): evaluating the impact of diabetes on mortality in patients with cancer

In this paper we address methodological aspects of aetiological importance in the link between diabetes and mortality in patients with cancer. We identified nine key points on the cancer pathway at which confounding may arise-cancer screening use, stage at diagnosis, cancer treatment selection, cancer treatment complications and failures, peri-treatment mortality, competing risks for long-term mortality, effects of type 2 diabetes on anti-cancer therapies, effects of glucose-lowering treatments on cancer outcome and differences in tumour biology. Two types of mortality studies were identified: (1) inception cohort studies that evaluate the effect of baseline diabetes on cancer-related mortality in general populations, and (2) cohorts of patients with a cancer diagnosis and pre-existing type 2 diabetes. We demonstrate, with multiple examples from the literature, that pre-existing diabetes affects presentation, cancer treatment, and outcome of several common cancer types, often to varying extents. Diabetes is associated with increased all-cause mortality in cancer patients, but the evidence that it influences cancer-specific mortality is inconsistent. In the absence of data that address the potential biases and confounders outlined in the above framework, we caution against the reporting of cancer-related mortality as a main endpoint in analyses determining the impact of diabetes and glucose-lowering medications on risk of cancer.

Impact of diabetes mellitus on the detection of prostate cancer via contemporary multi (≥ 12)-core prostate biopsy

BACKGROUND

Currently, controversy continues regarding the association between diabetes mellitus (DM) and prostate cancer (PCa). We investigated the impact of DM in PCa detection among men who underwent contemporary multi-core prostate biopsy.

METHODS

In this retrospective study, we reviewed records of 3,925 men who underwent multi (≥ 12)-core prostate biopsy at our institution. Biopsy outcomes were analyzed with respect to various variables, including DM, patient age, body mass index (BMI), prostate-specific antigen (PSA), digital rectal exam (DRE) finding, ultrasound finding, and prostate volume.

RESULTS

Among 3,925 subjects, 607 (15.5%) reported having DM at biopsy. Overall PCa was detected from biopsy in 1,387 (35.3%) patients, and high grade (biopsy Gleason score ≥ 7) PCa in 781 (19.9%). In multivariate analysis incorporating variables of patient age, BMI, PSA, DRE finding, ultrasound finding, and prostate volume, DM was observed to be significantly associated with higher odds of overall PCa detection via contemporary prostate biopsy (OR = 1.46, P = 0.019). When analyzed by tumor grade, DM was significantly associated with higher rate of high grade PCa detection from biopsy in multivariate analysis (OR = 1.54, P = 0.036) whereas DM and detection of low grade (biopsy Gleason score ≤ 6) PCa demonstrated no significant association (OR = 1.11, P = 0.558).

CONCLUSIONS

Our results showed DM was independently associated with the detection of high grade PCa via contemporary multi-core prostate biopsy. Further investigations would be needed to elucidate exact biologic basis of relationship between the two diseases.

The association of diabetes mellitus and high-grade prostate cancer in a multiethnic biopsy series

OBJECTIVE

To analyze the association of diabetes mellitus (DM) with risk of prostate cancer and cancer grade among men undergoing prostate biopsy and to analyze how obesity and race modify these associations.

MATERIALS AND METHODS

Retrospective analysis of 998 men from the Durham VA undergoing first prostate biopsy between 2001 and 2009 with complete data available. History of DM was determined by chart review. Patients' characteristics at biopsy were analyzed with chi-square and ranksum. Multivariable analyses of DM and risk of cancer and cancer grade were done using logistic regression adjusting for PSA, body mass index, race, age, year, and digital rectal exam.

RESULTS

At biopsy, 284 (28%) men had DM. DM was associated with African American (AAM; p = 0.010) and higher BMI (p < 0.001). DM was not associated with prostate cancer risk on either bivariate (p = 0.600) or multivariate analysis (p = 0.485). Similar results were found after stratification by race and obesity. In multivariable analysis, DM was associated with greater risk of high-grade disease (RR = 2.13, p = 0.024). The association was stronger among obese men (RR = 3.84, p = 0.020) and null in non-obese subjects (RR = 1.39, p = 0.460). After further stratification by race, DM was associated with high-grade disease only in obese Caucasian men (CM; RR = 5.81, p = 0.025) but not in obese AAM. DM was not associated with risk of low-grade disease in all men together or after stratification by obesity or race.

CONCLUSION

History of DM was associated with greater risk of high-grade disease. The association was strongest among obese CM suggesting the effect of DM on high-grade prostate cancer is modified by race and obesity.

Clinical outcomes after radical prostatectomy in diabetic patients treated with metformin

OBJECTIVES

To investigate the relationship between diabetes and metformin use with outcomes after radical prostatectomy (RP) for clinically localized cancer.

METHODS

A total of 112 diabetic metformin users and 98 diabetic non-metformin users treated with RP from 1990 to 2009 were identified. Nondiabetic controls were match using their 5-year risk of biochemical recurrence (BCR) as calculated by the preoperative Kattan nomogram.

RESULTS

A total of 616 patients were evaluated in this study. There was no significant difference between nondiabetic and diabetic patients, including metformin users, with respect to age, clinical stage, preoperative prostate-specific antigen (PSA) score, pathologic Gleason score, and pathologic stage. Diabetic patients, including metformin users, were more likely to be of African American or Hispanic background than were nondiabetic controls (P = .001). The estimated 5-year BCR-free survival was 75.0% for nondiabetic patients, compared with 66.1% for metformin users and 59.3% for diabetic non-metformin users (P = .004). In multivariate analysis, metformin use was not significantly associated with risk of BCR (HR = 0.94; 95% CI = 0.6-1.5, P = .817). However, being diabetic, regardless of metformin use, resulted in a 55% increase in risk of BCR (HR = 1.55; 95% CI = 1.03-2.33, P = .034).

CONCLUSIONS

Diabetes, regardless of metformin use, was significantly associated with an increased likelihood of BCR after RP. Metformin use did not prove to be of any benefit. These observations underscore the importance for further studies evaluating the metabolic pathways that affect prostate cancer biology.

The relationship between adiposity and gleason score in men with localized prostate cancer

BACKGROUND

We investigated the relationship between body mass index (BMI) at the time of cancer diagnosis and malignant phenotype as measured by Gleason score.

METHODS

This was a population-based cross-sectional study conducted on 1,096 prostate cancer patients treated for cure in Ontario, Canada between 1990 and 1998. An electronic-linked data set was enhanced by retrospective chart review. BMI was categorized as: normal (BMI <25.0), overweight (BMI 25.0-29.9), and obese (BMI ≥30). We also investigated the role of diabetic status. Gleason scores were categorized as: 2-4, 5-6, 7, and 8-10. We assessed the effect modification by patient age.

RESULTS

BMI was not associated with Gleason score; 9.7% of those with normal BMI had a Gleason score ≥8, and 9.4% fell into this Gleason category in both the overweight and obese groups (P = 0.73). 11.7% of diabetics had a Gleason score ≥8 compared to 9.3% in the non-diabetic group (P = 0.79). Both of these results persisted in a multivariate analysis controlling for age and diagnosis year. When stratified by age, only the Gleason score distribution in the youngest cohort (50- to 59-year olds) indicated higher Gleason scores in the obese group, with marginally significant results (P = 0.16).

CONCLUSIONS

With a possible exception in younger men, elevated BMI at the time of diagnosis does not appear to be associated with aspects of aggressive behavior associated with Gleason grade. The effect of adiposity on prostate cancer outcome is complex, requiring further study that includes attention to factors such as length of exposure, concomitant co-morbidities, and ethnicity.

Does diabetes mellitus increase the risk of high-grade prostate cancer in patients undergoing radical prostatectomy?

The objective was to test the hypothesis that in patients with prostate cancer undergoing radical prostatectomy (RP), diabetic patients are at a higher risk of harboring a high-grade tumor than non-diabetic patients. We examined 2060 consecutive men who underwent RP between 2001 and 2009. Of them, 7.1% had type 2 diabetes mellitus (DM). A high-grade tumor was defined as having a Gleason score ≥ 8. Univariable and multivariable logistic regression analyses were used to test the relationship between type 2 DM and high-grade tumor. Mean patient age was 64 years (range: 45-85). Mean total PSA level was 9 ng ml(-1) (range: 1-89.5). A significantly higher percentage of diabetic patients had high-grade tumor on biopsy (16.3 vs 7.6%; P = 0.001) and on RP specimen (21.1 vs 11.7%; P = 0.001) in comparison with non-diabetic patients. In multivariable analyses, DM was an independent predictor of high-grade tumor on biopsy (odds ratio = 2.31, P = 0.001) and on final pathological specimen (odds ratio = 2.22, P = 0.002). In patients undergoing RP, those with type 2 DM had a higher risk of harboring a poorly differentiated tumor on final pathological examination.

Glycemic control and prostate cancer progression: results from the SEARCH database

PURPOSE

Several studies have examined the association between diabetes mellitus (DM) and prostate cancer (PCa) risk and progression, however nearly all of these studies have compared diabetic versus non-diabetic men. We sought to investigate the role of glycemic control, as measured by HbA1c, on PCa aggressiveness and prognosis in men with DM and PCa from the Shared Equal Access Regional Cancer Hospital (SEARCH) database.

METHODS

We identified 247 men in SEARCH with DM and a recorded HbA1c value within the 12 months prior to radical prostatectomy between 1988 and 2009. We divided these men into tertiles by HbA1c level. The associations between HbA1c tertiles and risk of adverse pathology and biochemical recurrence were tested using multivariate logistic regression and Cox proportional hazards models, respectively.

RESULTS

Median HbA1c level was 6.9. On multivariate analysis, HbA1c tertiles were predictive of pathological Gleason score (P-trend = 0.001). Relative to the first tertile, men in the second (OR 4.68, P = 0.003) and third tertile (OR 6.60, P < 0.001) were more likely to have Gleason score > or = 4 + 3. HbA1c tertiles were not associated with margin status, node status, extracapsular extension or seminal vesicle invasion (all P-trend > 0.2). In the multivariate Cox proportional hazards model, increasing HbA1c tertiles were not significantly related to risk of biochemical recurrence (P-trend = 0.56).

CONCLUSION

Men with higher HbA1c levels presented with more biologically aggressive prostate tumors at radical prostatectomy. Although risk of recurrence was unrelated to HbA1c levels, further studies are needed to better explore the importance of glycemic control on long-term outcomes in diabetic men with PCa.

Diabetes and outcomes after radical prostatectomy: are results affected by obesity and race? Results from the shared equal-access regional cancer hospital database

BACKGROUND

Diabetes is associated with lower prostate cancer risk. The association of diabetes with prostate cancer outcomes is less clear. We examined the association between diabetes and outcomes after radical prostatectomy and tested whether associations varied by race and/or obesity.

MATERIALS AND METHODS

This study is a retrospective analysis of 1,262 men treated with radical prostatectomy between 1988 and 2008 within the Shared Equal-Access Regional Cancer Hospital database. We examined the multivariate association between diabetes at surgery and adverse pathology, biochemical recurrence (BCR), and prostate-specific antigen doubling time at recurrence using logistic, proportional hazards, and linear regression, respectively. Data were examined as a whole and stratified by race and obesity.

RESULTS

Diabetes was more prevalent among black (22% versus 15%, P < 0.001) and more obese men (P < 0.001). Diabetes was associated with higher tumor grade (odds ratio, 1.73; P = 0.002), seminal vesicle invasion (odds ratio, 1.73; P = 0.04), but not BCR (P = 0.67) or PSADT at recurrence (P = 0.12). In the secondary analysis, among white obese men, diabetes was associated with 2.5-fold increased BCR risk (P = 0.002) and a trend toward shorter PSADT, whereas among all other men (nonobese white men and black men), diabetes was associated with 23% lower recurrence risk (P = 0.09) and longer PSADT (P = 0.04).

CONCLUSION

In a radical prostatectomy cohort, diabetes was not associated with BCR. In the secondary analysis, diabetes was associated with more aggressive disease in obese white men and less aggressive disease for all other subsets. If externally validated, these findings suggest that among men with prostate cancer, the association between diabetes and prostate cancer aggressiveness may vary by race and obesity.

Does pre-existing diabetes affect prostate cancer prognosis? A systematic review

To summarize the influence of pre-existing diabetes on mortality and morbidity in men with prostate cancer. We searched MEDLINE and EMBASE from inception through 1 October 2008. Search terms were related to diabetes, cancer and prognosis. Studies were included if they reported an original data analysis of prostate cancer prognosis, compared outcomes between men with and without diabetes and were in English. Titles, abstracts and articles were reviewed independently by two authors. Conflicts were settled by consensus or third review. We abstracted data on study design, analytic methods, outcomes and quality. We summarized mortality and morbidity outcomes qualitatively and conducted a preliminary meta-analysis to quantify the risk of long-term (>3 months), overall mortality. In total, 11 articles were included in the review. Overall, one of four studies found increased prostate cancer mortality, one of two studies found increased nonprostate cancer mortality and one study found increased 30-day mortality. Data from four studies could be included in a preliminary meta-analysis for long-term, overall mortality and produced a pooled hazard ratio of 1.57 (95% CI: 1.12-2.20). Diabetes was also associated with receiving radiation therapy, complication rates, recurrence and treatment failure. Our analysis suggests that pre-existing diabetes affects the treatment and outcomes of men with prostate cancer.

Does diabetes mellitus modify the association between 17q12 risk variant and prostate cancer aggressiveness?

OBJECTIVE

To examine further the relationship between diabetes mellitus (DM), genotype and prostate cancer aggressiveness. Specifically, we sought to evaluate for effect modification between DM, a newly discovered prostate cancer susceptibility locus on chromosome 17q12 (single nucleotide polymorphism rs4430796) and prostate cancer features.

PATIENTS AND METHODS

In 593 genotyped men treated with radical prostatectomy (RP), we examined RP features stratified by DM and rs4430796 carrier status.

RESULTS

Despite a significantly higher body mass index among patients with DM, individual pathological features were similar between men with and without DM. Using a dominant model, 17q12 carriers were less likely to have DM and more likely to have a RP Gleason score of >or=7. However, the presence or absence of DM did not modify the relationship between 17q12 susceptibility alleles and pathological features.

CONCLUSION

Among 17q12 risk allele carriers, there was no significant relationship between DM and adverse tumour features. However, there were relatively few men with DM (7%) in our RP cohort, particularly compared with its 21% prevalence in the USA population aged >60 years. It is unclear whether this reflects selection bias, genetic protection from prostate cancer among patients with DM, or both. Despite these limitations, the present data suggest that DM alone does not appear to modify any association between 17q12 risk alleles with prostate cancer features.

Significance of preoperative HbA1c level in patients with diabetes mellitus and clinically localized prostate cancer

INTRODUCTION

We investigated potential relationships of history of diabetes mellitus (DM) and glycemic control, represented by hemoglobin A1c (HbA1c) level, with characteristics of tumor among patients who received radical prostatectomy (RP) for clinically localized prostate cancer.

METHODS

We reviewed data of 740 patients who underwent RP for clinically localized prostate cancer between 2004 and 2008 without receiving preoperative radiation or hormonal treatment. Univariate and multivariate logistic regression analyses addressed the associations of history of DM and HbA1c level with known prognostic variables of prostate cancer.

RESULTS

No significant differences were observed in various preoperative and pathological parameters between those with (n = 89) and without DM (n = 651). When only the subjects with DM were divided into two groups (group 1 and 2) according to HbA1c level (<6.5% vs. >/=6.5%), group 2 demonstrated significantly higher rate of extraprostatic extension of tumor (P = 0.043) and high (>/=7) pathological Gleason score (P = 0.005) than group 1. Also among those with DM, HbA1c level was observed to be an independent predictor for high pathologic Gleason score (P = 0.010) and extraprostatic extension of tumor (P = 0.035), respectively in multivariate analyses.

CONCLUSION

Although simple history of having DM may not be a significant factor regarding aggressiveness of clinically localized prostate cancer, the glycemic control, as represented by HbA1c level, may be a useful preoperative predictor of aggressive tumor profile among patients with DM who are also diagnosed with clinically localized prostate cancer.

Association of diabetes and body mass index with levels of prostate-specific antigen: implications for correction of prostate-specific antigen cutoff values?

BACKGROUND

In a recent study, an inverse association between diabetes and prostate-specific antigen (PSA) levels was observed, and several studies reported lower PSA levels in groups with higher body mass index. However, all of the studies were conducted in populations with intensive PSA screening and the role of diabetes severity, duration, and therapy are yet to be explored.

METHODS

Associations of diabetes duration and treatment, hemoglobin A1c, and BMI with PSA levels were assessed among 778 men ages 50 to 74 years, randomly chosen from the 2000 to 2002 baseline recruitment of a large population-based cohort study in Germany (prevalence of diabetes, 17%), using linear regression analyses.

RESULTS

PSA values were significantly reduced in men with insulin treatment (-39%; P = 0.006) and oral diabetic medication (-24%; P = 0.030), and in men with elevated (6.1-6.9%) and highly (> or =7%) elevated hemoglobin A1c values (-15%, P = 0.004 and -29%, P = 0.003, respectively). PSA reduction was not associated with duration of diabetes. Obesity was possibly associated with a reduction of PSA levels (-14%; P = 0.096).

CONCLUSIONS

Our study suggests that more severe forms of diabetes are associated with lower PSA levels and confirms the magnitude of reduction in PSA levels in diabetic men overall. The observed PSA reduction parallels reported risk reduction of prostate cancer among diabetic men.

Association of diabetes with prostate cancer risk in the multiethnic cohort

Among men of European ancestry, diabetics have a lower risk of prostate cancer than do nondiabetics. The biologic basis of this association is unknown. The authors have examined whether the association is robust across populations in a population-based prospective study. The analysis included 5,941 prostate cancer cases identified over a 12-year period (1993-2005) among 86,303 European-American, African-American, Latino, Japanese-American, and Native Hawaiian men from the Multiethnic Cohort. The association between diabetes and prostate-specific antigen (PSA) levels (n = 2,874) and PSA screening frequencies (n = 46,970) was also examined. Diabetics had significantly lower risk of prostate cancer than did nondiabetics (relative risk = 0.81, 95% confidence interval (CI): 0.74, 0.87; P < 0.001), with relative risks ranging from 0.65 (95% CI: 0.50, 0.84; P = 0.001) among European Americans to 0.89 (95% CI: 0.77, 1.03; P = 0.13) among African Americans. Mean PSA levels were significantly lower in diabetics than in nondiabetics (mean PSA levels, 1.07 and 1.28, respectively; P = 0.003) as were PSA screening frequencies (44.7% vs. 48.6%; P < 0.001); however, this difference could explain only a small portion ( approximately 20%) of the inverse association between these diseases. Diabetes is a protective factor for prostate cancer across populations, suggesting shared risk factors that influence a common mechanism.

Diabetes and mortality in men with locally advanced prostate cancer: RTOG 92-02

PURPOSE

Diabetes is associated with lower risk of prostate cancer. Most men with diabetes are obese, and obesity is associated with greater prostate cancer mortality. Whether diabetes influences outcomes after prostate cancer diagnosis is unknown.

PATIENTS AND METHODS

We assessed the relationship between prevalent diabetes and mortality using data from Radiation Therapy Oncology Group Protocol 92-02, a large randomized trial of men (N = 1,554) treated with radiation therapy and short-term versus long-term adjuvant goserelin for locally advanced prostate cancer. Regression and proportional hazard models were performed to evaluate relationships between prevalent diabetes and all-cause mortality, prostate cancer mortality, and non-prostate cancer mortality. Covariates included age, race, tumor stage, Gleason score, prostate-specific antigen, weight, and treatment arm.

RESULTS

There were a total of 765 deaths; 210 (27%) were attributed to prostate cancer. In univariate analyses, prevalent diabetes was associated with greater all-cause mortality and non-prostate cancer mortality but not prostate cancer mortality. After controlling for other covariates, prevalent diabetes remained significantly associated with greater all-cause mortality and non-prostate cancer mortality (hazard ratio [HR] = 2.12; 95% CI, 1.69 to 2.66; P < .0001) but not prostate cancer mortality (HR = 0.80; 95% CI, 0.51 to 1.25; P = .34). In contrast, weight was associated with greater prostate cancer mortality (HR = 1.77; 95% CI, 1.22 to 2.55; P = .002) but not all-cause or non-prostate cancer mortality.

CONCLUSION

Weight but not prevalent diabetes is associated with greater prostate cancer mortality in men receiving combined modality treatment for locally advanced disease. These observations suggest that the association between obesity and greater prostate cancer mortality is mediated by mechanism(s) other than the characteristic metabolic alterations of diabetes.

Diabetes mellitus and prostate cancer risk in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial

Objective

A history of diabetes has been fairly consistently related to a reduced prostate cancer risk, but previous investigations have not always addressed whether the relation with diabetes varies by prostate cancer aggressiveness or the association between diabetes and prostate cancer is modified by physical activity level and body mass, variables closely related to glucose metabolism.

Methods

We prospectively examined the diabetes–prostate cancer risk relationship among 33,088 men in the screening arm of the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial.

Results

During 8.9 years follow-up, we ascertained 2,058 incident prostate cancer cases. Diabetes history was related to decreased risk of total prostate cancer (RR = 0.80, 95% CI = 0.68–0.95). The apparent protection afforded by diabetes was primarily due to the inverse relation with non-aggressive disease (i.e., the combination of low grade (Gleason sum <8) and low stage (clinical stages I or II); RR = 0.75; 95% CI = 0.62–0.91). In contrast, no association was noted between diabetes and aggressive disease (i.e., high grade or high stage (Gleason sum ≥8 or clinical stages III or IV); RR = 1.04, 95% CI = 0.74–1.45). In further analyses, the association between diabetes and aggressive prostate cancer was suggestively positive for men who were lean (RR = 1.64, 95% CI = 0.87–3.07; BMI < 25 kg/m²) and it was positive for men who were the most physically active (RR = 1.63; 95% CI = 1.07–2.62; 3+ hours vigorous activity/week). By comparison, no relations of diabetes to aggressive prostate cancer were noted for their heavier or physically less active counterparts (p-value for tests of interaction = 0.10 and 0.03 BMI and physical activity, respectively).

Conclusion

In this study, diabetes showed divergent relations with prostate cancer by tumor aggressiveness. Specifically, diabetes was inversely associated with early stage prostate cancer but it showed no relation with aggressive prostate cancer. Exploratory analyses suggested a positive association between diabetes and aggressive prostate cancer in the subgroup of men with a low BMI.

Obesity, metabolic syndrome, and prostate cancer

Although obesity has been consistently linked to an increased risk of several malignancies, including cancers of the colon, gallbladder, kidney, and pancreas, its role in prostate cancer etiology remains elusive. Data on the association between obesity and prostate cancer incidence are inconsistent, and in some studies obesity is associated with an increase in risk of high-grade prostate cancer but with a decrease in risk of low-grade tumors. In contrast, obesity has been consistently associated with an increased risk of prostate cancer aggressiveness and mortality. The differential effects of obesity on subtypes of prostate cancer suggest etiologic heterogeneity in these tumors and complex interactions between androgen metabolism and several putative risk factors, including insulin resistance, diabetes, inflammation, and genetic susceptibility, on prostate cancer risk. Data on the role of abdominal obesity, insulin resistance, and metabolic syndrome in prostate cancer etiology are limited. Obesity has been shown to be associated with a state of low-grade chronic inflammation, and insulin resistance and the metabolic syndrome are associated with adverse metabolic profiles and with higher circulating concentrations of inflammation-related markers, including leptin, interleukin-6, and tumor necrosis factor-, many of which have been shown to enhance tumor growth. Thus, whether obesity and metabolic syndrome modulate the risk of prostate cancer through chronic inflammation needs to be investigated further. Given that the prevalence of obesity and metabolic syndrome is increasing worldwide and that the world population is aging, the roles of obesity and metabolic syndrome in prostate carcinogenesis warrant further clarification.

A meta-analysis of diabetes mellitus and the risk of prostate cancer

BACKGROUND

Studies investigating the association between diabetes mellitus and prostate cancer have reported inconsistent findings. We examined this association by conducting a detailed meta-analysis of the studies published on the subject.

METHODS

MEDLINE and EMBASE databases and bibliographies of retrieved articles were searched. Studies investigating the relationship between diabetes mellitus and prostate cancer were included in the meta-analysis. Potential sources of heterogeneity between studies were explored and publication bias was evaluated. Pooled relative risk (RR) was calculated using the random-effects model. Numerous relevant subgroup analyses were also done.

RESULTS

We included 19 studies, published between 1971 and 2005, in the meta-analysis and found an inverse association between diabetes mellitus and prostate cancer [RR, 0.84, 95% confidence interval (CI), 0.76-0.93, P for heterogeneity <or= 0.01]. For cohort studies alone, the RR was 0.81 (95% CI, 0.71-0.92, P for heterogeneity <or= 0.01) and for case-control studies alone, the RR was 0.89 (95% CI, 0.72-1.11, P for heterogeneity = 0.02). The significant heterogeneity was mitigated in some of the subgroup analyses. For studies conducted before prostate-specific antigen screening was introduced as a common procedure, the RR was 0.94 (95% CI, 0.85-1.03, P for heterogeneity = 0.15), and for studies conducted after this time, the RR was 0.73 (95% CI, 0.64-0.83, P for heterogeneity = 0.10). For studies that adjusted for three or more potential confounders, the RR was 0.74 (95% CI, 0.65-0.85, P for heterogeneity = 0.06) and for studies that adjusted for less than three potential confounders, the RR was 0.93 (95% CI, 0.86-1.02, P for heterogeneity = 0.18).

CONCLUSION

This study suggests an inverse relationship between diabetes and prostate cancer. Potential biological mechanisms underlying this association, as well as possible biases, are discussed.

History of diabetes mellitus and subsequent prostate cancer risk in the NIH-AARP Diet and Health Study

OBJECTIVE

A history of diabetes has been hypothesized to decrease prostate cancer risk, but studies have not always considered confounding or effect modification by dietary or lifestyle factors.

METHODS

We examined the association between diabetes history and subsequent prostate cancer risk in 328,316 men enrolled in the NIH-AARP Diet and Health Study. Participants were ages 50-71 years and without a prostate cancer diagnosis at baseline in 1995. A prior history of physician-diagnosed diabetes was assessed using a self-administered mailed questionnaire. Cases of prostate cancer were ascertained by matching the cohort to state cancer registries. Multivariable relative risks (RR) and 95% confidence intervals (CI) of prostate cancer were estimated using Cox regression.

RESULTS

During 5 years and 1,432,676 person-years of follow-up, 11,193 prostate cancer cases were ascertained. The age-adjusted and multivariable RRs of prostate cancer comparing men with diabetes to those without diabetes were 0.69 (95% CI=0.64, 0.74) and 0.71 (95% CI=0.66, 0.76), respectively, indicating no important confounding. The inverse association between diabetes and prostate cancer was particularly strong among men in the highest category of routine physical activity at work or home (RR=0.41; 95% CI=0.23, 0.74; p value for test of interaction = 0.03). Findings were similar for organ-confined and advanced prostate cancer.

CONCLUSION

Results from this large prospective study suggest that a history of diabetes is associated with a decreased risk of prostate cancer. The relationship strengthened with high levels of routine physical activity. Because increased physical activity is associated with lower circulating levels of insulin and testosterone, our findings support a role of hypoinsulinemia and low androgenicity linking diabetes to decreased prostate cancer risk.

Prostate-specific antigen values in diabetic and nondiabetic US men, 2001-2002

Recent studies have shown that diabetic men have a lower risk of prostate cancer and that this association may be related to time since diagnosis. The authors examined the association between diabetes and prostate-specific antigen (PSA) levels, controlling for potential confounders, in a nationally representative cross-sectional survey of the US population (National Health and Nutrition Examination Survey 2001-2002). Diabetes classification was self-reported, and undiagnosed diabetes was determined with fasting plasma glucose measurements. Controlling for age, men with self-reported diabetes had a 21.6% lower geometric mean PSA level than men without diabetes. The difference increased with years since diagnosis (>10 years: 27.5% lower geometric mean PSA level). Overweight men who had had diabetes for more than 10 years had a predicted geometric mean PSA level 40.8% lower than that of nondiabetic, normal-weight men. These results are consistent with the hypothesis that long-term diabetes is associated with a lower risk of prostate cancer. The mechanism of this association may involve the regulation of PSA by androgens, although the authors are unable to confirm this assertion. Better understanding of the determinants of PSA level is needed to make the distinction between factors affecting the PSA test's accuracy and those altering the risk of prostate cancer.

Diabetes and the risk of prostate cancer: the role of diabetes treatment and complications

Epidemiologic evidence suggests diabetic men have a slightly lower prostate cancer risk than non-diabetic men. We examined this association in a prospective cohort study of 35 239 men, 50-76 years old, in Washington State who completed a baseline questionnaire between 2000 and 2002. Incident prostate cancers as of 31 December 2004 were identified through the SEER registry. Diabetic men had a slightly lower risk of prostate cancer than non-diabetic men (hazard ratio (HR) 0.83, 95% confidence interval (CI) 0.64-1.07). Insulin users overall and insulin users with diabetic complications had decreased risks, compared to non-diabetic men (HR 0.49, 95% CI 0.26-0.92) and (HR 0.36, 95% CI 0.15-0.87), respectively. Oral medication use for diabetes was not associated with prostate cancer. Insulin is likely a marker of severity of diabetes. Future studies of this association should consider diabetes type, treatment, severity, complications and biomarkers.